Influence Of Target Stimulating Properties And Display Duration On The Stroop Dilution Effect

Stroop effect was defined as the interference of word meaning to the to-be-named color. Generally, word reading was different from color recognition in cognitive process. In 1935, John Riddly Stroop used the contradictions between stimulus'color and meaning in his experiment, such as wrote "red" in blue, subjects were asked to spell the color of the word, not spell the meaning, so the right answer was "blue". It found that spell the color was interfered by the word meaning. Stroop dilution effect was defined as when the irrelevant word increased as the color word distractor in the word-bar carrier Paradigm, Stroop effect will be widely weakened. Now, there are four accounts of the Stroop dilution effect that have been proposed:attentional capture, early visual interference, unlimited-capacity attention capture and Domain-Specific Limited-Capacity Processing. Through the analysis and comparison of these theories, finding that each theory has both advantages and disadvantages. Domain-Specific Limited-Capacity Processing account make up the deficiency of the first three theory, but there was no objective standard to estimate whether the material properties were same or not. Besides, there is no in-depth research to the position and display duration of the stimulus. Thus, Taking characters as experimental material and exploring the mechanism of the Stroop dilution effect with three experiments. Target stimulus was divided into three categories: color bar, neutral word and digit, distraction stimulus was color word. The experiment used within-subjects design, The program was established by software E-prime, seventy-eight undergraduates were investigated. The results shows:(1) Using characters, a Stroop dilution effect is observed when the properties of the target stimulus (neutral word) is same as the distractor stimulus (color word); when the properties of the target stimulus (digit) is different from the distractor stimulus (color word), there is no Stroop dilution effect. The Domain-Specific Limited-Capacity Processing account was confirmed by these results. (2) when the properties of the target stimulus and the distractor stimulus are from in the same domain, If the subjects was instructed to process the distractors, according to the assumption of Domain-Specific Limited-Capacity Processing account, target stimulus should be disturbed, exerting strong Stroop effect, but the result was just the opposite. This can't be explaned well with Domain-Specific Limited-Capacity Processing. It means that only spatial attention does not necessarily make the distractor stimulus get processed or processed in the primary perception stage, can't reach semantic level, then can't interfere with the target stimulus, also no Stroop effect would occur. (3) Investigated the trend of Stroop effect changing with duration in the three different targets conditions, the results showed that subjects allocated to the distractors more time and more resources with the time increasing, the processing lever was from sensory or perception processing to semantic processing. Finally the conclusion is that the processing level of distraction stimulation depends on the target stimulating properties presented at fixation and display duration. When the duration is long enough, the nature of the tagers did not affect the intensity of Stroop effect; Otherwise, it will affect.